Bus bar unit and motor

ABSTRACT

A bus bar unit includes a bus bar holder on one side in an axial direction of an annular stator around a central axis extending in a vertical direction, a bus bar extending along a plane perpendicular to the axial direction and fixed to the bus bar holder, and an external connection terminal connected to the bus bar and extending upward from the bus bar. The bus bar includes a wire and a terminal connector located on one end thereof and connected to the external connection terminal, a first lead wire connector located on the other end thereof and connected to a lead wire extending from the stator, a second lead wire connector located between the terminal connector and the first lead wire connector, and a first linear portion to connect the first and second lead wire connectors and having a linear shape when viewed in the axial direction. Each of the first and the second lead wire connectors has a U-shape that opens in a radial direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a U.S. national stage of PCT Application No. PCT/JP2018/011184,filed on Mar. 20, 2018, and priority under 35 U.S.C. § 119(a) and 35U.S.C. § 365(b) is claimed from U.S. Provisional Application No.62/479,490, filed on Mar. 31, 2017, and Japanese Application No.2017-191446, filed Sep. 29, 2017; the entire contents of each of whichare hereby incorporated herein by reference.

1. Field of the Invention

The present disclosure relates to a bus bar unit and a motor.

2. Background

A motor provided with a bus bar unit is known. The bus bar unit includesa bus bar to which coils of each phase of a motor are connected. Aconnector for supplying power from the outside of the motor to the coilsof each phase is connected to the bus bar.

For example, there have been prior arts involving bar units providedwith a ring-shaped bus bar (bus ring) extending along a circumferentialdirection of a motor. In the bus bar unit, the bus bar is formed bybending a wire.

In the bus bar unit, bus bars are arranged on an outer side of a statorin a radial direction. Further, the bus bars of each phase are arrangedconcentrically at intervals in the radial direction of a motor. Thus, adimension of the bus bar unit in the radial direction is increased. Asthe dimension of the bus bar in the radial direction increases, thelength of a wire required to constitute the bus bar increases.

SUMMARY

Example embodiments of the present disclosure provide bus bar units eachcapable of being miniaturized and saving wire required to provide a busbar.

One aspect of an example embodiment of the present disclosure provides abus bar unit that is provided in a motor and includes a bus bar holderprovided on one side in an axial direction of a stator disposed in anannular shape around a central axis extending in a vertical direction, abus bar extending along a plane perpendicular to the axial direction andfixed to the bus bar holder, and an external connection terminalconnected to the bus bar and extending upward from the bus bar. The busbar includes a wire and a terminal connector located on one end thereofand connected to the external connection terminal, a first lead wireconnector located on the other end thereof and connected to a lead wireextending from the stator, a second lead wire connector located betweenthe terminal connector and the first lead wire connector, and a firstlinear portion to connect the first lead wire connector to the secondlead wire connector and having a linear shape when viewed in the axialdirection. Each of the first lead wire connector and the second leadwire connector have a U-shape that opens in a radial direction.

The above and other elements, features, steps, characteristics andadvantages of the present disclosure will become more apparent from thefollowing detailed description of the example embodiments with referenceto the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective exploded view illustrating a stator and a busbar unit of a motor according to an example embodiment of the presentdisclosure.

FIG. 2 is a cross-sectional plan view illustrating a configuration of astator according to an example embodiment of the present disclosure.

FIG. 3 is a perspective view illustrating the configuration of a statoraccording to an example embodiment of the present disclosure.

FIG. 4 is a perspective view illustrating a bus bar unit according to anexample embodiment of the present disclosure.

FIG. 5 is a perspective view illustrating a bus bar holder according toan example embodiment of the present disclosure.

FIG. 6 is a plan view illustrating a state in which bus bars areassembled to a bus bar holder according to an example embodiment of thepresent disclosure.

FIG. 7 is a perspective view illustrating a state in which a U-phase busbar group is assembled to a bus bar holder according to an exampleembodiment of the present disclosure.

FIG. 8 is a perspective view illustrating a state in which a U-phase busbar group and a V-phase bus bar group are assembled to a bus bar holderaccording to an example embodiment of the present disclosure.

FIG. 9 is a view illustrating an apparatus to which a motor according toan example embodiment of the present disclosure is mounted.

DETAILED DESCRIPTION

FIG. 1 is a perspective exploded view illustrating a stator and a busbar unit of a motor according to the present example embodiment. FIG. 2is a cross-sectional plan view illustrating a configuration of thestator according to the example embodiment. FIG. 3 is a perspective viewillustrating the configuration of the stator according to the exampleembodiment. Further, in FIG. 1, FIG. 2, and FIG. 3, a specific drawingof coils is omitted.

As shown in FIG. 1, a motor 10 of the present example embodimentincludes a rotor 30 (see FIG. 2), a stator 40, a housing (not shown),and a bus bar unit 60.

As shown in FIG. 2, the rotor 30 includes a shaft 31 and a rotor core32. The shaft 31 is disposed along a central axis J extending in avertical direction.

In the following description, a direction parallel to the central axis Jis simply referred to as a “vertical direction” (axial direction), aradial direction about the central axis J is simply referred to as a“radial direction”, and a circumferential direction about the centralaxis J is simply referred to as a “circumferential direction”. Further,an upper side in FIG. 1 in the vertical direction is simply referred toas an “upper side”, and a lower side in FIG. 1 in the vertical directionis simply referred to as a “lower side”. Further, the upper side, thelower side, and the vertical direction are simply names for describingthe relative positional relationship of each part, and the actualarrangement relationship or the like is not limited.

The rotor core 32 is a cylindrical member. When viewed in the verticaldirection, an outer shape of the rotor core 32 is a polygonal shape. Inthe present example embodiment, the outer shape of the rotor core 32 isan octagonal shape. That is, in the present example embodiment, therotor core 32 is an approximately hollow octagonal column. Further, therotor core 32 may be a cylinder or the like. The rotor core 32 is alaminated steel plate in which a plurality of electromagnetic steelplates are laminated in the vertical direction.

The rotor core 32 includes a shaft through hole 32 h at a centerthereof. The shaft 31 passes through the shaft through hole 32 h. Theshaft 31 may be fixed to the rotor core 32 by press-fitting, adhesion,or the like, or may be fixed by a resin member or the like. That is, theshaft 31 is fixed directly or indirectly to the rotor core 32. The shaft31 may be a hollow member and is not particularly limited.

In the present example embodiment, a dimension of the rotor core 32 inthe vertical direction is the same as a dimension of a stator core 41 inthe vertical direction, which is to be described below. However, thedimension of the rotor core 32 may be different from the dimension ofthe stator core 41.

A plurality of magnets 33 are disposed on each outer side surface of therotor core 32. The magnet 33 is a plate-shaped member extending in thevertical direction. Adjacent magnets 33 face each other in acircumferential direction. The magnet 33 located on one side in thecircumferential direction faces the magnet 33 located on the other sidein the circumferential direction with a gap in the circumferentialdirection.

In the present example embodiment, a dimension of the magnet 33 in thevertical direction is the same as the dimension of the rotor core 32 inthe vertical direction. An upper surface of the magnet 33 is flush withan upper surface of the rotor core 32. A lower surface of the magnet 33is flush with a lower surface of the rotor core 32. That is, thedimension of the magnet 33 in the vertical direction is the same as thedimension of the stator core 41 in the vertical direction. In addition,the dimension of the magnet 33 in the vertical direction may bedifferent from the dimension of the stator core 41 in the verticaldirection.

The stator 40 is disposed on an outer side of the rotor 30 in a radialdirection. As shown in FIGS. 2 and 3, the stator 40 is disposed aroundthe central axis J in an annular shape. The stator 40 is accommodated inthe housing (not shown) having a cylindrical shape. The stator 40includes the stator core 41 having an annular shape, an insulator 42mounted on the stator core 41, and coils (not shown) mounted on thestator core 41 through the insulator 42.

The stator core 41 is a laminated steel plate in which a plurality ofelectromagnetic steel plates are laminated in the vertical direction.The stator core 41 includes a core back part 41 a having an annularshape and a plurality of teeth 41 b. In the present example embodiment,the stator core 41 is a so-called split core. The core back part 41 a isconfigured by connecting a plurality of fan-shaped core pieces 46 in thecircumferential direction. The tooth 41 b is provided on an innercircumferential surface of each of the core pieces 46. The tooth 41 bextends inward in the radial direction from the inner circumferentialsurface of the core piece 46. The teeth 41 b are arranged at equalintervals in the circumferential direction on an inner side surface ofthe core back part 41 a. The tooth 41 b faces the magnet 33 of the rotor30 in the radial direction. The tooth 41 b includes an umbrella 41 c atan inner end thereof in the radial direction. The umbrella 41 c extendsfrom the inner end of the tooth 41 b in the radial direction to bothsides in the circumferential direction. A gap is formed between adjacentumbrellas 41 c in the circumferential direction.

Further, the stator core 41 is not limited to the split core and may beother types of cores such as a so-called straight core or round core.

The material of the insulator 42 has insulation. In the present exampleembodiment, the material of the insulator 42 is an insulating resin. Theinsulator 42 covers at least a portion of an outer circumferentialsurface of the tooth 41 b.

The insulator 42 includes a flange part 42 f on an upper side of thestator 40. The flange part 42 f is located on an outer side of theinsulator 42 in the radial direction. The flange part 42 f has apredetermined height in the vertical direction and extends in thecircumferential direction.

Further, the material of the insulator 42 is not limited to the resinand any other material may be used as long as it has insulation.

The motor 10 of the present example embodiment is a so-calledthree-phase motor having three phases of a U-phase, a V-phase, and aW-phase. The coils (not shown) include four U-phase coils, four V-phasecoils, and four W-phase coils. In the present example embodiment, a coilconnection method is a so-called Y-connection method. The U-phase coils,the V-phase coils, and the W-phase coils are arranged adjacent to eachother in this order in the circumferential direction. In the presentexample embodiment, there are four sets of coils, each including theU-phase coil, the V-phase coil, and the W-phase coil.

In the coil (not shown), a coil wire is wound around the tooth 41 bthrough the insulator 42.

As shown in FIG. 3, each coil (the U-phase coil, the V-phase coil, andthe W-phase coil) includes a first lead wire 44 and a second lead wire45. The first lead wire 44 and the second lead wire 45 extend upward. Ineach coil, the first lead wire 44 is located on an outer side of theradial direction with respect to the second lead wire 45. Further, ineach coil, the second lead wire 45 extends upward longer than the firstlead wire 44 in the vertical direction. In the present exampleembodiment, one first lead wire 44 and one second lead wire 45 are drawnout from each coil. In the present example embodiment, the number ofteeth 41 b is twelve. Thus, the number of coils 43 is twelve. The numberof first lead wires 44 is twelve, and the number of second lead wires 45is twelve.

The first lead wires of the U-phase coil, the V-phase coil, and theW-phase coil of each set are electrically connected to each other by aneutral point bus bar 48. The neutral point bus bar 48 is held by theflange part 42 f of the insulator 42. The neutral point bus bar 48 isformed by bending a conductive metal wire. In the present exampleembodiment, four neutral point bus bars 48 are arranged at equalintervals in the circumferential direction.

Each of the neutral point bus bars 48 includes a bus bar main body 48 aand a coil wire holding part 48 b. The bus bar main body 48 a has an arcshape extending in the circumferential direction when viewed in thevertical direction.

The coil wire holding parts 48 b are provided at a plurality of placesspaced in a circumferential direction of the bus bar main body 48 a. Inthe present example embodiment, the coil wire holding parts 48 b areprovided at four places of the bus bar main body 48 a. Each of the coilwire holding parts 48 b has a U-shape that opens outward in the radialdirection. Each coil wire holding part 48 b includes a pair of stretchedparts 48 c, 48 c and a connection part 48 d. The pair of stretched parts48 c, 48 c extend inward in the radial direction from the bus bar mainbody 48 a. The connection part 48 d connects inner side ends of the pairof stretched parts 48 c, 48 c in the radial direction to each other. Theconnection part 48 d has a semicircular arc shape.

The first lead wires 44 of the U-phase coil, the V-phase coil, and theW-phase coil of each set are electrically connected to each neutralpoint bus bar 48. A front end of each of a first lead wire 44U of theU-phase coil, a first lead wire 44V of the V-phase coil, and a firstlead wire 44W of the W-phase coil is located on an inner side of thecoil wire holding part 48 b. In this manner, ends of the three firstlead wires 44U, 44V, and 44W drawn out from the U-phase coil, theV-phase coil, and the W-phase coil of each set are electricallyconnected to one neutral point bus bar 48. Each coil wire holding part48 b and the first lead wire 44 are fixed by caulking. Further, eachcoil wire holding part 48 b and the end of the first lead wire 44 arefirmly fixed by laser welding or the like.

FIG. 4 is a perspective view illustrating the bus bar unit according tothe example embodiment.

As shown in FIG. 4, the bus bar unit 60 has an approximately circularplate shape in which the entire bus bar unit 60 expands in the radialdirection. The bus bar unit 60 includes bus bars 70 and a bus bar holder61.

The bus bar holder 61 is provided on one side of the stator 40 in thevertical direction. In the present example embodiment, the bus barholder 61 is disposed on the upper side of the stator 40.

The bus bar holder 61 is made of an insulating material. In the presentexample embodiment, the material of the bus bar holder 61 is aninsulating resin. However, the material of the bus bar holder 61 may beother insulating materials.

FIG. 5 is a perspective view illustrating the bus bar holder accordingto the example embodiment.

As shown in FIG. 5, the bus bar holder 61 is an approximatelyplate-shaped member. When viewed in the vertical direction, an outershape of the bus bar holder 61 is an approximately circular shape. Thebus bar holder 61 has a rotationally symmetrical shape at every 120°centered on the central axis J. The bus bar holder 61 includes a throughhole 61 h passing through a center portion thereof in the verticaldirection. The bus bar holder 61 is fitted into an inner side of thehousing (not shown) in the radial direction.

The bus bar holder 61 includes a lead wire insertion hole 62. The leadwire insertion hole 62 passes through the bus bar holder 61 in thevertical direction. A plurality of lead wire insertion holes 62 areprovided at intervals in the circumferential direction. In the presentexample embodiment, the number of lead wire insertion holes 62 is thesame as the number of second lead wires 45. That is, the number of leadwire insertion holes 62 is twelve.

The bus bar holder 61 includes a clamping part 66 and a terminal holdingpart 69 on an upper surface thereof.

The clamping part 66 is provided on an outer side of the through hole 61h of the bus bar holder 61 in the radial direction. The clamping part 66is provided on the inner side in the radial direction with respect tothe lead wire insertion hole 62. A plurality of clamping parts 66 areprovided at intervals in the circumferential direction. In the presentexample embodiment, six clamping parts 66 are provided at equalintervals in the circumferential direction. Each of the clamping parts66 includes a pair of claw members 66 a. Each of the claw members 66 aextends upward. The pair of claw members 66 a face each other with a gapin the radial direction. Each of the pair of claw members 66 a includesa protrusion (not shown) at a front end thereof protruding in adirection in which the claw members 66 a face each other. A separationdistance between the protrusions of the pair of claw members 66 a isnarrower than an outer diameter of a wire 77 of the bus bar 70 to bedescribed below. Thus, the clamping part 66 holds the wire 77 of the busbar 70 by snap fitting.

The terminal holding part 69 is provided on an outer circumference ofthe bus bar holder 61. A plurality of terminal holding parts 69 areprovided in the circumferential direction. In the present exampleembodiment, three terminal holding parts 69 are provided at intervals inthe circumferential direction. Each of the terminal holding parts 69includes a pair of columnar members 69 a and 69 b. The pair of columnarmembers 69 a and 69 b face each other at an interval in the radialdirection. Each of the columnar members 69 a and 69 b extends upwardfrom an upper surface of the bus bar holder 61. The columnar members 69a and 69 b include holding grooves 69 m and 69 n, respectively. Theholding grooves 69 m and 69 n are provided on inner sides of thecolumnar members 69 a and 69 b, which face each other in an oppositedirection. The holding grooves 69 m and 69 n extend in the verticaldirection. Upper ends of the holding grooves 69 m and 69 n are openupward at upper ends of the columnar members 69 a and 69 b.

As shown in FIG. 1, the bus bar holder 61 is located above the firstlead wire 44 extending upward from each coil of the stator 40. Thesecond lead wire 45 passes through the lead wire insertion hole 62 andprotrudes to the upper surface side of the bus bar holder 61.

FIG. 6 is a plan view illustrating a state in which the bus bars areassembled to the bus bar holder according to the example embodiment.

As shown in FIGS. 5 and 6, the bus bars 70 are located on an upper sideof the bus bar holder 61. The bus bars 70 are fixed to the bus barholder 61. The bus bars 70 include a U-phase bus bar group (first typebus bar) 70U, a V-phase bus bar group (second type bus bar) 70V, and aW-phase bus bar group (third type bus bar) 70W.

The U-phase bus bar group 70U includes a U-phase first bus bar 71 and aU-phase second bus bar 72. The V-phase bus bar group 70V includes aV-phase first bus bar 73 and a V-phase second bus bar 74. The W-phasebus bar group 70W includes a W-phase first bus bar 75 and a W-phasesecond bus bar 76.

Each of the U-phase first bus bar 71, the U-phase second bus bar 72, theV-phase first bus bar 73, the V-phase second bus bar 74, the W-phasefirst bus bar 75, and the W-phase second bus bar 76 extends along aplane perpendicular to the vertical direction.

Each of the U-phase first bus bar 71, the U-phase second bus bar 72, theV-phase first bus bar 73, the V-phase second bus bar 74, the W-phasefirst bus bar 75, and the W-phase second bus bar 76 is composed of thewire 77 having a circular cross-section. The wire 77 is made of aconductive metal material. Each of the U-phase first bus bar 71, theU-phase second bus bar 72, the V-phase first bus bar 73, the V-phasesecond bus bar 74, the W-phase first bus bar 75, and the W-phase secondbus bar 76 is formed by bending the wire 77 using a forming machine. Theforming machine bends the wire 77 at a predetermined position whilefeeding out the wire 77. In the forming machine, a bending position, abending direction, the curvature of a bending portion, and the like ofthe wire 77 may be set in advance. In this manner, the U-phase first busbar 71, the U-phase second bus bar 72, the V-phase first bus bar 73, theV-phase second bus bar 74, the W-phase first bus bar 75, and the W-phasesecond bus bar 76 are automatically manufactured by the forming machineon the basis of the preset programming.

FIG. 7 is a perspective view illustrating a state in which the U-phasebus bar group is assembled to the bus bar holder according to theexample embodiment.

As shown in FIGS. 6 and 7, the U-phase first bus bar 71 includes a firstlinear part 71 s, a second linear part 71 t, a terminal connection part71 c, a first lead wire connection part (lead wire connection part) 71a, and a second lead wire connection part (lead wire connection part) 71b.

The first linear part 71 s is provided between the first lead wireconnection part 71 a and the second lead wire connection part 71 b. Thefirst linear part 71 s connects the first lead wire connection part 71 ato the second lead wire connection part 71 b. The first linear part 71 shas a linear shape when viewed in the vertical direction. The firstlinear part 71 s extends in a direction perpendicular to the radialdirection.

The second linear part 71 t is provided between the second lead wireconnection part 71 b and the terminal connection part 71 c. The secondlinear part 71 t extends from a fourth end 71 i to be described below.The second linear part 71 t has a linear shape when viewed in thevertical direction. The second linear part 71 t is parallel to the firstlinear part 71 s. The second linear part 71 t is disposed to be shiftedinward in the radial direction with respect to an imaginary line Lextending the first linear part 71 s.

The terminal connection part 71 c is located on one end of the U-phasefirst bus bar 71. The terminal connection part 71 c is bent about 90°inward in the radial direction from an end of the second linear part 71t, and extends in a direction perpendicular to the radial direction. Theterminal connection part 71 c is connected to a U-phase externalconnection terminal 81.

The first lead wire connection part 71 a is located on the other end ofthe U-phase first bus bar 71. The first lead wire connection part 71 aincludes a pair of stretched parts 71 v and a curved part 71 w. The pairof stretched parts 71 v extend parallel to each other along the radialdirection. The pair of stretched parts 71 v are disposed on both sidesof the lead wire insertion hole 62 of the bus bar holder 61 with thelead wire insertion hole 62 of the bus bar holder 61 interposedtherebetween. The curved part 71 w connects outer ends of the pair ofstretched parts 71 v in the radial direction. The curved part 71 w has asemicircular arc shape and curves along an inner circumference edge ofthe lead wire insertion hole 62. As described above, the first lead wireconnection part 71 a has a U-shape that opens inward in the radialdirection. The first lead wire connection part 71 a includes an opening71 p that opens inward in the radial direction. The first lead wireconnection part 71 a is connected to the second lead wire 45 protrudingupward from the bus bar holder 61. The second lead wire 45 is located onan inner side of the first lead wire connection part 71 a. The secondlead wire 45 is joined to the first lead wire connection part 71 a bylaser welding or the like.

The first lead wire connection part 71 a further includes a first end 71d and a second end 71 e. The first end 71 d is connected to an end ofthe first linear part 71 s. The second end 71 e is located on theopposite side of the first end 71 d. The second end 71 e is providedwith an extending part 71 f extending in a direction away from theopening 71 p of the first lead wire connection part 71 a. The extendingpart 71 f extends in a direction perpendicular to the radial direction.

The second lead wire connection part 71 b is located between theterminal connection part 71 c and the first lead wire connection part 71a. The second lead wire connection part 71 b is located between thesecond linear part 71 t and the first linear part 71 s. The second leadwire connection part 71 b has the same shape as the first lead wireconnection part 71 a. That is, the second lead wire connection part 71 bincludes a pair of stretched parts 71 v and a curved part 71 w. Asdescribed above, the second lead wire connection part 71 b has a U-shapethat opens inward in the radial direction. The second lead wireconnection part 71 b includes an opening 71 p that opens inward in theradial direction.

The second lead wire connection part 71 b is connected to a second leadwire 45 protruding upward from the bus bar holder 61. The second leadwire 45 is located on an inner side of the second lead wire connectionpart 71 b. The second lead wire 45 is joined to the second lead wireconnection part 71 b by laser welding or the like.

The second lead wire connection part 71 b further includes a third end71 h and the fourth end 71 i. The third end 71 h is connected to the endof the first linear part 71 s. The fourth end 71 i is located on theopposite side of the third end 71 h. The fourth end 71 i is connected toan end of the second linear part 71 t.

The U-phase first bus bar 71 is held by a clamping part 66 at the firstlinear part 71 s. In other words, the U-phase first bus bar 71 is heldby the clamping part 66 between the first lead wire connection part 71 aand the second lead wire connection part 71 b. The first lead wireconnection part 71 a and the second lead wire connection part 71 b arearranged on a concentric circle centered on the central axis J whenviewed in the vertical direction.

The U-phase second bus bar 72 includes a first linear part 72 s, asecond linear part 72 t, a terminal connection part 72 c, a first leadwire connection part (lead wire connection part) 72 a, and a second leadwire connection part (lead wire connection part) 72 b.

The first linear part 72 s is provided between the first lead wireconnection part 72 a and the second lead wire connection part 72 b. Thefirst linear part 72 s connects the first lead wire connection part 72 ato the second lead wire connection part 72 b. The first linear part 72 shas a linear shape when viewed in the vertical direction. The firstlinear part 72 s extends in a direction perpendicular to the radialdirection.

The second linear part 72 t is provided between the second lead wireconnection part 72 b and the terminal connection part 72 c. The secondlinear part 72 t extends from a fourth end 72 i to be described below.The second linear part 72 t has a linear shape when viewed in thevertical direction. The second linear part 72 t is parallel to the firstlinear part 72 s. The second linear part 72 t is disposed to be shiftedinward in the radial direction with respect to an imaginary line Lextending the first linear part 72 s.

The terminal connection part 72 c is located on one end of the U-phasesecond bus bar 72. The terminal connection part 72 c is bent about 90°inward in the radial direction from an end of the second linear part 72t, and extends in a direction perpendicular to the radial direction. Theterminal connection part 72 c is disposed to be shifted outward in theradial direction with respect to the terminal connection part 71 c ofthe U-phase first bus bar 71. The terminal connection part 72 c isdisposed parallel to the terminal connection part 71 c of the U-phasefirst bus bar 71. The terminal connection part 72 c is connected to theU-phase external connection terminal 81.

The first lead wire connection part 72 a is located on the other end ofthe U-phase second bus bar 72. The first lead wire connection part 72 ahas the same shape as the first lead wire connection part 71 a. Thefirst lead wire connection part 72 a has a U-shape that opens inward inthe radial direction. The first lead wire connection part 72 a includesan opening 72 p that opens inward in the radial direction. The firstlead wire connection part 72 a is connected to a second lead wire 45protruding upward from the bus bar holder 61. The second lead wire 45 islocated on an inner side of the first lead wire connection part 72 a.The second lead wire 45 is joined to the first lead wire connection part72 a by laser welding or the like.

The first lead wire connection part 72 a further includes a first end 72d and a second end 72 e. The first end 72 d is connected to an end ofthe first linear part 72 s. The second end 72 e is located on theopposite side of the first end 72 d. The second end 72 e is providedwith an extending part 72 f extending in a direction away from theopening 72 p of the first lead wire connection part 72 a. The extendingpart 72 f extends in a direction perpendicular to the radial direction.

The second lead wire connection part 72 b is located between theterminal connection part 72 c and the first lead wire connection part 72a. The second lead wire connection part 72 b is located between thesecond linear part 72 t and the first linear part 72 s. The second leadwire connection part 72 b has the same shape as the second lead wireconnection part 71 b. The second lead wire connection part 72 b has aU-shape that opens inward in the radial direction. The second lead wireconnection part 72 b includes an opening 72 p that opens inward in theradial direction. The second lead wire connection part 72 b is connectedto a second lead wire 45 protruding upward from the bus bar holder 61.The second lead wire 45 is located on an inner side of the second leadwire connection part 72 b. The second lead wire 45 is joined to thesecond lead wire connection part 72 b by laser welding or the like.

The second lead wire connection part 72 b further includes a third end72 h and the fourth end 72 i. The third end 72 h is connected to an endof the first linear part 72 s. The fourth end 72 i is located on theopposite side of the third end 72 h. The fourth end 72 i is connected toan end of the second linear part 72 t.

The U-phase second bus bar 72 is held by a clamping part 66 at the firstlinear part 72 s. In other words, the U-phase second bus bar 72 is heldby the clamping part 66 between the first lead wire connection part 72 aand the second lead wire connection part 72 b. The U-phase first bus bar71 and the U-phase second bus bar 72 are held along the upper surface ofthe bus bar holder 61. The U-phase first bus bar 71 and the U-phasesecond bus bar 72 may be spaced apart from the upper surface of the busbar holder 61 or may be in contact with the upper surface of the bus barholder 61.

In the entire U-phase first bus bar 71 and the entire U-phase second busbar 72 including the first linear part 71 s, the terminal connectionpart 71 c and the first lead wire connection part 71 a, and the firstlinear part 72 s, the terminal connection part 72 c and the first leadwire connection part 72 a respectively, vertical positions coincide witheach other.

The first lead wire connection part 72 a and the second lead wireconnection part 72 b are arranged on a concentric circle centered on thecentral axis J when viewed in the vertical direction. Further, the firstlead wire connection part 72 a and the second lead wire connection part72 b, and the first lead wire connection part 71 a and the second leadwire connection part 71 b of the U-phase first bus bar 71 are arrangedon a concentric circle centered on the central axis J when viewed in thevertical direction.

In the U-phase first bus bar 71 and the U-phase second bus bar 72, thefirst linear part 71 s and the first linear part 72 s are located on theopposite sides with respect to the central axis J. Further, in theU-phase first bus bar 71 and the U-phase second bus bar 72, the firstlinear part 71 s and the first linear part 72 s extend in parallel.

Further, the U-phase first bus bar 71 and the U-phase second bus bar 72extend to mutually opposite sides in the circumferential direction fromthe U-phase external connection terminal 81 connected thereto.

As a result, a magnetic field generated by the U-phase first bus bar 71and a magnetic field generated by the U-phase second bus bar 72 canceleach other, so that influence on the outside is suppressed.

FIG. 8 is a perspective view illustrating a state in which the U-phasebus bar group and the V-phase bus bar group are assembled to the bus barholder according to the example embodiment.

As shown in FIGS. 6 and 8, the V-phase first bus bar 73 includes a firstlinear part 73 s, a second linear part 73 t, a terminal connection part73 c, a first lead wire connection part (lead wire connection part) 73a, and a second lead wire connection part (lead wire connection part) 73b.

The first linear part 73 s is provided between the first lead wireconnection part 73 a and the second lead wire connection part 73 b. Thefirst linear part 73 s connects the first lead wire connection part 73 ato the second lead wire connection part 73 b. The first linear part 73 shas a linear shape when viewed in the vertical direction. The firstlinear part 73 s extends in a direction perpendicular to the radialdirection.

The second linear part 73 t is provided between the second lead wireconnection part 73 b and the terminal connection part 73 c. The secondlinear part 73 t extends from a fourth end 73 i to be described below.The second linear part 73 t has a linear shape when viewed in thevertical direction. The second linear part 73 t is parallel to the firstlinear part 73 s. The second linear part 73 t is disposed to be shiftedinward in the radial direction with respect to an imaginary line Lextending the first linear part 73 s.

The terminal connection part 73 c is located on one end of the V-phasefirst bus bar 73. The terminal connection part 73 c is bent about 90°inward in the radial direction from an end of the second linear part 73t, and extends in a direction perpendicular to the radial direction. Theterminal connection part 73 c is connected to a V-phase externalconnection terminal 82.

The first lead wire connection part 73 a is located on the other end ofthe V-phase first bus bar 73. The first lead wire connection part 73 ahas the same shape as the first lead wire connection part 71 a. Thefirst lead wire connection part 73 a has a U-shape that opens inward inthe radial direction.

The first lead wire connection part 73 a is connected to a second leadwire 45 protruding upward from the bus bar holder 61. The second leadwire 45 is located on an inner side of the first lead wire connectionpart 73 a. The second lead wire 45 is joined to the first lead wireconnection part 73 a by laser welding or the like.

The first lead wire connection part 73 a further includes a first end 73d and a second end 73 e. The first end 73 d is connected to an end ofthe first linear part 73 s. The second end 73 e is located on theopposite side of the first end 73 d. The second end 73 e is providedwith an extending part 73 f extending in a direction away from anopening 73 p of the first lead wire connection part 73 a. The extendingpart 73 f extends in a direction perpendicular to the radial direction.

The second lead wire connection part 73 b is located between theterminal connection part 73 c and the first lead wire connection part 73a. The second lead wire connection part 73 b is located between thesecond linear part 73 t and the first linear part 73 s. The second leadwire connection part 73 b has the same shape as the second lead wireconnection part 71 b. The second lead wire connection part 73 b has aU-shape that opens inward in the radial direction. The second lead wireconnection part 73 b includes an opening 73 p that opens inward in theradial direction.

The second lead wire connection part 73 b is connected to a second leadwire 45 protruding upward from the bus bar holder 61. The second leadwire 45 is located on an inner side of the second lead wire connectionpart 73 b. The second lead wire 45 is joined to the second lead wireconnection part 73 b by laser welding or the like.

The second lead wire connection part 73 b further includes a third end73 h and the fourth end 73 i. The third end 73 h is connected to an endof the first linear part 73 s. The fourth end 73 i is located on theopposite side of the third end 73 h. The fourth end 73 i is connected toan end of the second linear part 73 t.

The V-phase first bus bar 73 is held by a clamping part 66 at the firstlinear part 73 s. In other words, the V-phase first bus bar 73 is heldby the clamping part 66 between the first lead wire connection part 73 aand the second lead wire connection part 73 b.

The first lead wire connection part 73 a and the second lead wireconnection part 73 b are arranged on a concentric circle centered on thecentral axis J when viewed in the vertical direction.

The V-phase first bus bar 73 includes a cross part J1 crossing a portionof the U-phase second bus bar 72 when viewed in the vertical direction.The V-phase first bus bar 73 includes a retracting part 93 at the crosspart J1. The retracting part 93 passes above the U-phase second bus bar72 where the retracting part 93 intersects. The retracting part 93passes above the first linear part 72 s of the U-phase second bus bar72. The retracting part 93 is provided on the first linear part 73 s ofthe V-phase first bus bar 73. The retracting part 93 is provided on thesecond lead wire connection part 73 b side in the first linear part 73s. The retracting part 93 includes a pair of leg parts 93 a and a bridgepart 93 b. The pair of leg parts 93 a extend upward from the firstlinear part 73 s and the second lead wire connection part 73 b. Thebridge part 93 b connects upper-end portions of the pair of leg parts 93a to each other. The bridge part 93 b is located above the first linearpart 73 s. The bridge part 93 b extends parallel to the first linearpart 73 s. In this manner, the retracting part 93 straddles an upperside of the first linear part 72 s of the U-phase second bus bar 72. Theretracting part 93 is spaced apart from the first linear part 72 s ofthe U-phase second bus bar 72.

The V-phase second bus bar 74 includes a first linear part 74 s, asecond linear part 74 t, a terminal connection part 74 c, a first leadwire connection part (lead wire connection part) 74 a, and a second leadwire connection part (lead wire connection part) 74 b.

The first linear part 74 s is provided between the first lead wireconnection part 74 a and the second lead wire connection part 74 b. Thefirst linear part 74 s connects the first lead wire connection part 74 ato the second lead wire connection part 74 b. The first linear part 74 shas a linear shape when viewed in the vertical direction. The firstlinear part 74 s extends in a direction perpendicular to the radialdirection.

The second linear part 74 t is provided between the second lead wireconnection part 74 b and the terminal connection part 74 c. The secondlinear part 74 t extends from a fourth end 74 i to be described below.The second linear part 74 t has a linear shape when viewed in thevertical direction. The second linear part 74 t is parallel to the firstlinear part 74 s. The second linear part 74 t is disposed to be shiftedinward in the radial direction with respect to an imaginary line Lextending the first linear part 74 s.

The terminal connection part 74 c is located on one end of the V-phasesecond bus bar 74. The terminal connection part 74 c is bent about 90°inward in the radial direction from an end of the second linear part 74t, and extends in a direction perpendicular to the radial direction. Theterminal connection part 74 c is disposed to be shifted outward in theradial direction with respect to the terminal connection part 73 c ofthe V-phase first bus bar 73. The terminal connection part 74 c isdisposed parallel to the terminal connection part 73 c of the V-phasefirst bus bar 73. The terminal connection part 74 c is connected to theV-phase external connection terminal 82.

The first lead wire connection part 74 a is located on the other end ofthe V-phase second bus bar 74. The first lead wire connection part 74 ahas the same shape as the first lead wire connection part 71 a. Thefirst lead wire connection part 74 a has a U-shape that opens inward inthe radial direction. The first lead wire connection part 74 a includesan opening 74 p that opens inward in the radial direction. The firstlead wire connection part 74 a is connected to a second lead wire 45protruding upward from the bus bar holder 61. The second lead wire 45 islocated on an inner side of the first lead wire connection part 74 a.The second lead wire 45 is joined to the first lead wire connection part74 a by laser welding or the like.

The first lead wire connection part 74 a further includes a first end 74d and a second end 74 e. The first end 74 d is connected to an end ofthe first linear part 74 s. The second end 74 e is located on theopposite side of the first end 74 d. The second end 74 e is providedwith an extending part 74 f extending in a direction away from theopening 74 p of the first lead wire connection part 74 a. The extendingpart 74 f extends in a direction perpendicular to the radial direction.

The second lead wire connection part 74 b is located between theterminal connection part 74 c and the first lead wire connection part 74a. The second lead wire connection part 74 b is located between thesecond linear part 74 t and the first linear part 74 s. The second leadwire connection part 74 b has the same shape as the second lead wireconnection part 71 b. The second lead wire connection part 74 b has aU-shape that opens inward in the radial direction. The second lead wireconnection part 74 b includes an opening 74 p that opens inward in theradial direction.

The second lead wire connection part 74 b is connected to a second leadwire 45 protruding upward from the bus bar holder 61. The second leadwire 45 is located on an inner side of the second lead wire connectionpart 74 b. The second lead wire 45 is joined to the second lead wireconnection part 74 b by laser welding or the like.

The second lead wire connection part 74 b further includes a third end74 h and the fourth end 74 i. The third end 74 h is connected to an endof the first linear part 74 s. The fourth end 74 i is located on theopposite side of the third end 74 h. The fourth end 74 i is connected toan end of the second linear part 74 t.

The V-phase second bus bar 74 includes a cross part J2 crossing aportion of the U-phase first bus bar 71 when viewed in the verticaldirection. The V-phase second bus bar 74 includes a retracting part 94at the cross part J2. The retracting part 94 passes above the U-phasefirst bus bar 71 where the retracting part 94 intersects. The retractingpart 94 passes above the first linear part 71 s of the U-phase first busbar 71. The retracting part 94 is provided on the first linear part 74 sof the V-phase second bus bar 74. The retracting part 94 is provided onthe first lead wire connection part 74 a side in the first linear part74 s. The retracting part 94 has the same shape as the retracting part93. The retracting part 94 straddles an upper side of the first linearpart 71 s of the U-phase first bus bar 71. The retracting part 94 isspaced apart from the first linear part 71 s of the U-phase first busbar 71.

The V-phase second bus bar 74 is held by a clamping part 66 at the firstlinear part 74 s. In other words, the V-phase second bus bar 74 is heldby the clamping part 66 between the first lead wire connection part 74 aand the second lead wire connection part 74 b. The V-phase first bus bar73 and the V-phase second bus bar 74 are arranged at an angle differentfrom the U-phase first bus bar 71 and the U-phase second bus bar 72 by120° in the circumferential direction.

The V-phase first bus bar 73 and the V-phase second bus bar 74 held bythe clamping parts 66 are arranged along the upper surface of the busbar holder 61. The V-phase first bus bar 73 and the V-phase second busbar 74 may be spaced apart from the upper surface of the bus bar holder61 or may be in contact with the upper surface of the bus bar holder 61.

The vertical positions of the V-phase first bus bar 73 and the V-phasesecond bus bar 74 coincide with those of the U-phase first bus bar 71and the U-phase second bus bar 72 at the first linear part 73 s, thesecond linear part 73 t, the terminal connection part 73 c, the firstlead wire connection part 73 a, and the second lead wire connection part73 b, and the first linear part 74 s, the second linear part 74 t, theterminal connection part 74 c, the first lead wire connection part 74 a,and the second lead wire connection part 74 b. In other words, thevertical positions of the V-phase first bus bar 73 and the V-phasesecond bus bar 74 coincide with those of the U-phase first bus bar 71and the U-phase second bus bar 72 at portions other than the retractingparts 93 and 94.

The first lead wire connection part 74 a and the second lead wireconnection part 74 b are arranged on a concentric circle centered on thecentral axis J when viewed in the vertical direction. Further, the firstlead wire connection part 74 a and the second lead wire connection part74 b, and the first lead wire connection part 73 a and the second leadwire connection part 73 b of the V-phase first bus bar 73 are arrangedon a concentric circle centered on the central axis J when viewed in thevertical direction.

In the V-phase first bus bar 73 and the V-phase second bus bar 74, thefirst linear part 73 s and the first linear part 74 s are located on theopposite sides with respect to the central axis J. Further, in theV-phase first bus bar 73 and the V-phase second bus bar 74, the firstlinear part 73 s and the first linear part 74 s extend in parallel.

Further, the V-phase first bus bar 73 and the V-phase second bus bar 74extend to mutually opposite sides in the circumferential direction fromthe V-phase external connection terminal 82 connected thereto.

As a result, a magnetic field generated by the V-phase first bus bar 73and a magnetic field generated by the V-phase second bus bar 74 canceleach other, so that influence on the outside is suppressed.

As shown in FIG. 6, the W-phase first bus bar 75 includes a first linearpart 75 s, a second linear part 75 t, a terminal connection part 75 c, afirst lead wire connection part (lead wire connection part) 75 a, and asecond lead wire connection part (lead wire connection part) 75 b.

The first linear part 75 s is provided between the first lead wireconnection part 75 a and the second lead wire connection part 75 b. Thefirst linear part 75 s connects the first lead wire connection part 75 ato the second lead wire connection part 75 b. The first linear part 75 shas a linear shape when viewed in the vertical direction. The firstlinear part 75 s extends in a direction perpendicular to the radialdirection.

The second linear part 75 t is provided between the second lead wireconnection part 75 b and the terminal connection part 75 c. The secondlinear part 75 t extends from a fourth end 75 i to be described below.The second linear part 75 t has a linear shape when viewed in thevertical direction. The second linear part 75 t is parallel to the firstlinear part 75 s. The second linear part 75 t is disposed to be shiftedinward in the radial direction with respect to an imaginary line Lextending the first linear part 75 s.

The terminal connection part 75 c is located on one end of the W-phasefirst bus bar 75. The terminal connection part 75 c is bent about 90°inward in the radial direction from an end of the second linear part 75t, and extends in a direction perpendicular to the radial direction. Theterminal connection part 75 c is connected to a W-phase externalconnection terminal 83.

The first lead wire connection part 75 a is located on the other end ofthe W-phase first bus bar 75. The first lead wire connection part 75 ahas the same shape as the first lead wire connection part 71 a. Thefirst lead wire connection part 75 a has a U-shape that opens inward inthe radial direction. The first lead wire connection part 75 a includesan opening 75 p that opens inward in the radial direction.

The first lead wire connection part 75 a is connected to a second leadwire 45 protruding upward from the bus bar holder 61. The second leadwire 45 is located on an inner side of the first lead wire connectionpart 75 a. The second lead wire 45 is joined to the first lead wireconnection part 75 a by laser welding or the like.

The first lead wire connection part 75 a further includes a first end 75d and a second end 75 e. The first end 75 d is connected to an end ofthe first linear part 75 s. The second end 75 e is located on theopposite side of the first end 75 d. The second end 75 e is providedwith an extending part 75 f extending in a direction away from theopening 75 p of the first lead wire connection part 75 a. The extendingpart 75 f extends in a direction perpendicular to the radial direction.

The second lead wire connection part 75 b is located between theterminal connection part 75 c and the first lead wire connection part 75a. The second lead wire connection part 75 b is located between thesecond linear part 75 t and the first linear part 75 s. The second leadwire connection part 75 b has the same shape as the second lead wireconnection part 71 b. The second lead wire connection part 75 b has aU-shape that opens inward in the radial direction. The second lead wireconnection part 75 b includes an opening 75 p that opens inward in theradial direction.

The second lead wire connection part 75 b is connected to a second leadwire 45 protruding upward from the bus bar holder 61. The second leadwire 45 is located on an inner side of the second lead wire connectionpart 75 b. The second lead wire 45 is joined to the second lead wireconnection part 75 b by laser welding or the like.

The second lead wire connection part 75 b further includes a third end75 h and the fourth end 75 i. The third end 75 h is connected to an endof the first linear part 75 s. The fourth end 75 i is located on theopposite side of the third end 75 h. The fourth end 75 i is connected toan end of the second linear part 75 t.

The W-phase first bus bar 75 is held by a clamping part 66 at the firstlinear part 75 s. In other words, the W-phase first bus bar 75 is heldby the clamping part 66 between the first lead wire connection part 75 aand the second lead wire connection part 75 b.

The first lead wire connection part 75 a and the second lead wireconnection part 75 b are arranged on a concentric circle centered on thecentral axis J when viewed in the vertical direction.

The W-phase first bus bar 75 includes cross parts J3 and J4.

The cross part J3 intersects a portion of the U-phase second bus bar 72when viewed in the vertical direction. The W-phase first bus bar 75includes a retracting part 93A at the cross part J3. The retracting part93A passes above the U-phase second bus bar 72 where the retracting part93A intersects. The retracting part 93A passes above the first linearpart 72 s of the U-phase second bus bar 72. The retracting part 93A isprovided on the first linear part 75 s of the W-phase first bus bar 75.The retracting part 93A is provided on the first lead wire connectionpart 75 a side in the first linear part 75 s.

The cross part J4 intersects a portion of the V-phase second bus bar 74when viewed in the vertical direction. The W-phase first bus bar 75includes a retracting part 93B at the cross part J4. The retracting part93B passes above the V-phase second bus bar 74 where the retracting part93B intersects. The retracting part 93B passes above the first linearpart 74 s of the V-phase second bus bar 74. The retracting part 93B isprovided on the first linear part 75 s of the W-phase first bus bar 75.The retracting part 93B is provided on the second lead wire connectionpart 75 b side in the first linear part 75 s.

The retracting parts 93A and 93B have the same shape as the retractingpart 93. The retracting parts 93A and 93B straddle upper sides of thefirst linear part 72 s of the U-phase second bus bar 72 and the firstlinear part 74 s of the V-phase second bus bar 74. The retracting part93A and 93B is disposed at an interval between the first linear part 72s of the U-phase second bus bar 72 and the first linear part 74 s of theV-phase second bus bar 74.

The W-phase second bus bar 76 includes a first linear part 76 s, asecond linear part 76 t, a terminal connection part 76 c, a first leadwire connection part (lead wire connection part) 76 a, and a second leadwire connection part (lead wire connection part) 76 b.

The first linear part 76 s is provided between the first lead wireconnection part 76 a and the second lead wire connection part 76 b. Thefirst linear part 76 s connects the first lead wire connection part 76 ato the second lead wire connection part 76 b. The first linear part 76 shas a linear shape when viewed in the vertical direction. The firstlinear part 76 s extends in a direction perpendicular to the radialdirection.

The second linear part 76 t is provided between the second lead wireconnection part 76 b and the terminal connection part 76 c. The secondlinear part 76 t extends from a fourth end 76 i to be described below.The second linear part 76 t has a linear shape when viewed in thevertical direction. The second linear part 76 t is parallel to the firstlinear part 76 s. The second linear part 76 t is disposed to be shiftedinward in the radial direction with respect to an imaginary line Lextending the first linear part 76 s.

The terminal connection part 76 c is located on one end of the W-phasesecond bus bar 76. The terminal connection part 76 c is bent about 90°inward in the radial direction from an end of the second linear part 76t, and extends in a direction perpendicular to the radial direction. Theterminal connection part 76 c is disposed to be shifted outward in theradial direction with respect to the terminal connection part 75 c ofthe W-phase first bus bar 75. The terminal connection part 76 c isdisposed parallel to the terminal connection part 75 c of the W-phasefirst bus bar 75. The terminal connection part 76 c is connected to theW-phase external connection terminal 83.

The first lead wire connection part 76 a is located on the other end ofthe W-phase second bus bar 76. The first lead wire connection part 76 ais connected to a second lead wire 45 protruding upward from the bus barholder 61. The first lead wire connection part 76 a has the same shapeas the first lead wire connection part 71 a. The first lead wireconnection part 76 a has a U-shape that opens inward in the radialdirection. The first lead wire connection part 76 a includes an opening76 p that opens inward in the radial direction. The second lead wire 45is located on an inner side of the first lead wire connection part 76 a.The second lead wire 45 is joined to the first lead wire connection part76 a by laser welding or the like.

The first lead wire connection part 76 a further includes a first end 76d and a second end 76 e. The first end 76 d is connected to an end ofthe first linear part 76 s. The second end 76 e is located on theopposite side of the first end 76 d. The second end 76 e is providedwith an extending part 76 f extending in a direction away from theopening 76 p of the first lead wire connection part 76 a. The extendingpart 76 f extends in a direction perpendicular to the radial direction.

The second lead wire connection part 76 b is located between theterminal connection part 76 c and the first lead wire connection part 76a. The second lead wire connection part 76 b is located between thesecond linear part 76 t and the first linear part 76 s. The second leadwire connection part 76 b has the same shape as the second lead wireconnection part 71 b. The second lead wire connection part 76 b has aU-shape that opens inward in the radial direction. The second lead wireconnection part 76 b includes an opening 76 p that opens inward in theradial direction.

The second lead wire connection part 76 b is connected to a second leadwire 45 protruding upward from the bus bar holder 61. The second leadwire 45 is located on an inner side of the second lead wire connectionpart 76 b. The second lead wire 45 is joined to the second lead wireconnection part 76 b by laser welding or the like.

The second lead wire connection part 76 b further includes a third end76 h and the fourth end 76 i. The third end 76 h is connected to an endof the first linear part 76 s. The fourth end 76 i is located on theopposite side of the third end 76 h. The fourth end 76 i is connected toan end of the second linear part 76 t.

The W-phase second bus bar 76 includes cross parts J5 and J6.

The cross part J5 intersects a portion of the V-phase first bus bar 73when viewed in the vertical direction. The W-phase second bus bar 76includes a retracting part 94A at the cross part J5. The retracting part94A passes above the V-phase first bus bar 73 where the retracting part94A intersects. The retracting part 94A passes above the first linearpart 73 s of the V-phase first bus bar 73. The retracting part 94A isprovided on the first linear part 76 s of the W-phase second bus bar 76.The retracting part 94A is provided on the first lead wire connectionpart 76 a side in the first linear part 76 s.

The cross part J6 intersects a portion of the U-phase first bus bar 71when viewed in the vertical direction. The W-phase second bus bar 76includes a retracting part 94B at the cross part J6. The retracting part94B passes above the U-phase first bus bar 71 where the retracting part94B intersects. The retracting part 94B passes above the first linearpart 71 s of the U-phase first bus bar 71. The retracting part 94B isprovided on the first linear part 76 s of the W-phase second bus bar 76.The retracting part 94B is provided on the second lead wire connectionpart 76 b side in the first linear part 76 s.

The retracting parts 94A and 94B have the same shape as the retractingpart 93. The retracting parts 94A and 94B straddle upper sides of thefirst linear part 73 s of the V-phase first bus bar 73 and the firstlinear part 71 s of the U-phase first bus bar 71. The retracting part94A and 94B is disposed at an interval between the first linear part 73s of the V-phase first bus bar 73 and the first linear part 71 s of theU-phase first bus bar 71.

The W-phase second bus bar 76 is held by a clamping part 66 at the firstlinear part 76 s. In other words, the W-phase second bus bar 76 is heldby the clamping part 66 between the first lead wire connection part 76 aand the second lead wire connection part 76 b. The W-phase first bus bar75 and the W-phase second bus bar 76 are arranged at an angle differentfrom the U-phase first bus bar 71 and the U-phase second bus bar 72, andthe V-phase first bus bar 73 and the V-phase second bus bar 74 by 120°in the circumferential direction, respectively.

The W-phase first bus bar 75 and the W-phase second bus bar 76 held bythe clamping parts 66 are arranged along the upper surface of the busbar holder 61. The W-phase first bus bar 75 and the W-phase second busbar 76 may be spaced apart from the upper surface of the bus bar holder61 or may be in contact with the upper surface of the bus bar holder 61.

The vertical positions of the W-phase first bus bar 75 and the W-phasesecond bus bar 76 coincide with those of the U-phase first bus bar 71and the U-phase second bus bar 72 at the first linear part 75 s, thesecond linear part 75 t, the terminal connection part 75 c, the firstlead wire connection part 75 a, and the second lead wire connection part75 b, and the first linear part 76 s, the second linear part 76 t, theterminal connection part 76 c, the first lead wire connection part 76 a,and the second lead wire connection part 76 b. In other words, thevertical positions of the W-phase first bus bar 75 and the W-phasesecond bus bar 76 coincide with those of the U-phase first bus bar 71and the U-phase second bus bar 72 at portions other than the retractingparts 93A, 93B, 94A, and 94B.

The first lead wire connection part 76 a and the second lead wireconnection part 76 b are arranged on a concentric circle centered on thecentral axis J when viewed in the vertical direction. Further, the firstlead wire connection part 76 a and the second lead wire connection part76 b, and the first lead wire connection part 75 a and the second leadwire connection part 75 b of the W-phase first bus bar 75 are arrangedon a concentric circle centered on the central axis J when viewed in thevertical direction.

In the W-phase first bus bar 75 and the W-phase second bus bar 76, thefirst linear part 75 s and the first linear part 76 s are located on theopposite sides with respect to the central axis J. Further, in theW-phase first bus bar 75 and the W-phase second bus bar 76, the firstlinear part 75 s and the first linear part 76 s extend in parallel.

Further, the W-phase first bus bar 75 and the W-phase second bus bar 76extend to mutually opposite sides in the circumferential direction fromthe W-phase external connection terminal 83 connected thereto.

As a result, a magnetic field generated by the W-phase first bus bar 75and a magnetic field generated by the W-phase second bus bar 76 canceleach other, so that influence on the outside is suppressed.

As shown in FIG. 4, a plurality of external connection terminals 80 areprovided on the upper surface of the bus bar holder 61. In the presentexample embodiment, the external connection terminals 80 include theU-phase external connection terminal 81, the V-phase external connectionterminal 82, and the W-phase external connection terminal 83. Each ofthe U-phase external connection terminal 81, the V-phase externalconnection terminal 82, and the W-phase external connection terminal 83is connected to the bus bar 70 and extends upward from bus bar 70. Eachof the U-phase external connection terminal 81, the V-phase externalconnection terminal 82, and the W-phase external connection terminal 83is composed of a terminal member 85 having a common shape.

The terminal member 85 is made of a conductive metal material. Theterminal member 85 is a plate-shaped member and extends upward. Theterminal member 85 includes a terminal stretched part 86 and a terminalbase part 87. The terminal stretched part 86 is connected to a connector(not shown) of an external device.

The terminal base part 87 is held by the terminal holding part 69 of thebus bar holder 61. Both side ends of the columnar members 69 a and 69 bin a width direction are inserted into the holding grooves 69 m and 69n.

The terminal member 85 includes a bus bar holding groove 89. The bus barholding groove 89 is formed on a lower end of the terminal base part 87.The bus bar holding groove 89 has a U-shape and opens toward a lowerside of the terminal base part 87. Two bus bar holding grooves 89 areprovided at an interval in the width direction of the terminal base part87.

As shown in FIG. 7, the terminal connection part 71 c of the U-phasefirst bus bar 71 and the terminal connection part 72 c of the U-phasesecond bus bar 72 are inserted into the bus bar holding grooves 89, 89of the U-phase external connection terminal 81, respectively. The busbar holding grooves 89, 89 of the U-phase external connection terminal81 and the terminal connection parts 71 c and 72 c are joined by laserwelding or the like.

As shown in FIG. 8, the terminal connection part 73 c of the V-phasefirst bus bar 73 and the terminal connection part 74 c of the V-phasesecond bus bar 74 are inserted into the bus bar holding grooves 89, 89of the V-phase external connection terminal 82, respectively. The busbar holding grooves 89, 89 of the V-phase external connection terminal82 and the terminal connection parts 73 c and 74 c are joined by laserwelding or the like.

As shown in FIG. 4, the terminal connection part 75 c of the W-phasefirst bus bar 75 and the terminal connection part 76 c of the W-phasesecond bus bar 76 are inserted into the bus bar holding grooves 89, 89of the W-phase external connection terminal 83, respectively. The busbar holding grooves 89, 89 of the W-phase external connection terminal83 and the terminal connection parts 75 c and 76 c are joined by laserwelding or the like.

In order to assemble the above-described bus bar holder 61, first, theU-phase first bus bar 71 and the U-phase second bus bar 72 are assembledto the bus bar holder 61 as shown in FIG. 7. Here, the first linear part71 s of the U-phase first bus bar 71 and the first linear part 72 s ofthe U-phase second bus bar 72 are each fitted into the clamping part 66by snap fitting. In this manner, a front end of each of the second leadwires 45 is inserted into each of the first lead wire connection part 71a and the second lead wire connection part 71 b of the U-phase first busbar 71, and each of the first lead wire connection part 72 a and thesecond lead wire connection part 72 b of the U-phase second bus bar 72.

Next, the V-phase first bus bar 73 and the V-phase second bus bar 74 areassembled to the bus bar holder 61 as shown in FIG. 8. Here, the firstlinear part 73 s of the V-phase first bus bar 73 and the first linearpart 74 s of the V-phase second bus bar 74 are each fitted into theclamping part 66 by snap fitting. In this manner, a front end of each ofthe second lead wires 45 is inserted into each of the first lead wireconnection part 73 a and the second lead wire connection part 73 b ofthe V-phase first bus bar 73, and each of the first lead wire connectionpart 74 a and the second lead wire connection part 74 b of the V-phasesecond bus bar 74.

Next, the W-phase first bus bar 75 and the W-phase second bus bar 76 areassembled to the bus bar holder 61 as shown in FIG. 4. Here, the firstlinear part 75 s of the W-phase first bus bar 75 and the first linearpart 76 s of the W-phase second bus bar 76 are each fitted into theclamping part 66 by snap fitting. In this manner, a front end of each ofthe second lead wires 45 is inserted into each of the first lead wireconnection part 75 a and the second lead wire connection part 75 b ofthe W-phase first bus bar 75, and each of the first lead wire connectionpart 76 a and the second lead wire connection part 76 b of the W-phasesecond bus bar 76.

Subsequently, each terminal member 85 is attached to each terminalholding part 69. Thus, the terminal connection part 71 c of the U-phasefirst bus bar 71 and the terminal connection part 72 c of the U-phasesecond bus bar 72 are inserted into the bus bar holding grooves 89, 89of the U-phase external connection terminal 81, respectively. Theterminal connection part 73 c of the V-phase first bus bar 73 and theterminal connection part 74 c of the V-phase second bus bar 74 areinserted into the bus bar holding grooves 89, 89 of the V-phase externalconnection terminal 82. The terminal connection part 75 c of the W-phasefirst bus bar 75 and the terminal connection part 76 c of the W-phasesecond bus bar 76 are inserted into the bus bar holding grooves 89, 89of the W-phase external connection terminal 83.

Next, each of a plurality of bus bars (the U-phase first bus bar 71, theU-phase second bus bar 72, the V-phase first bus bar 73, the V-phasesecond bus bar 74, the W-phase first bus bar 75, and the W-phase secondbus bar 76) is welded to each second lead wire 45. Here, each of thelead wire connection parts 71 a, 71 b, 72 a, 72 b, 73 a, 73 b, 74 a, 74b, 75 a, 75 b, 76 a, and 76 b is welded to each second lead wire 45.

For example, the U-phase first bus bar 71 will be described as anexample. As shown in FIG. 6, in order to weld the first lead wireconnection part 71 a of the U-phase first bus bar 71 and the second leadwire 45, the pair of stretched parts 71 v that are fitted through awelding jig 100 from the outside maintains. In this state, the firstlead wire connection part 71 a and the second lead wire 45 are welded bylaser welding or the like. The first lead wire connection part 71 aincludes the first linear part 71 s and the extending part 71 f on bothsides thereof through the first end 71 d and the second end 71 e. Here,when a positional displacement occurs in the welding jig 100 fitting thefirst lead wire connection part 71 a, the welding jig 100 is broughtinto contact with the first linear part 71 s and the extending part 71f. Thus, further positional displacement of the welding jig 100 issuppressed, so that the first lead wire connection part 71 a is securelyheld by welding jig 100.

In order to weld the first lead wire connection part 71 b of the U-phasefirst bus bar 71 and the second lead wire 45, the pair of stretchedparts 71 v that are fitted through a welding jig 100 from the outsidemaintains. In this state, the second lead wire connection part 71 b andthe second lead wire 45 are welded by laser welding or the like. Thesecond lead wire connection part 71 b includes the first linear part 71s and the second linear part 71 t on both sides thereof through thethird end 71 h and the fourth end 71 i. Here, when a positionaldisplacement occurs in the welding jig 100 fitting the second lead wireconnection part 71 b, the welding jig 100 is brought into contact withthe first linear part 71 s and the second linear part 71 t. Thus, thesecond lead wire connection part 71 b is securely held by the weldingjig 100.

In the same manner, welding is performed while holding each lead wireconnection part by the welding jig 100 on the U-phase second bus bar 72,the V-phase first bus bar 73, the V-phase second bus bar 74, the W-phasefirst bus bar 75, and the W-phase second bus bar 76.

The welding of each second lead wire 45 and each of the U-phase firstbus bar 71, the U-phase second bus bar 72, the V-phase first bus bar 73,the V-phase second bus bar 74, the W-phase first bus bar 75, and theW-phase second bus bar 76 is sequentially performed by rotating the busbar holder 61 about the central axis J with respect to a laserirradiation nozzle that performs laser welding and the welding jig 100.

Thereafter, the U-phase external connection terminal 81, the V-phaseexternal connection terminal 82, and the W-phase external connectionterminal 83 are welded to the U-phase first bus bar 71 and U-phasesecond bus bar 72, the V-phase first bus bar 73 and the V-phase secondbus bar 74, and the W-phase first bus bar 75 and the W-phase second busbar 76, respectively.

Thereby, the assembly of the bus bar unit 60 is completed.

According to the present example embodiment, the bus bars 70 (theU-phase first bus bar 71, the U-phase second bus bar 72, the V-phasefirst bus bar 73, the V-phase second bus bar 74, the W-phase first busbar 75, and the W-phase second bus bar 76) are each composed of the wire77. As described above, by using the wire 77 for the bus bar 70, the busbar 70 may be manufactured by a forming machine. Thus, the need for amold for manufacturing the bus bar 70 is eliminated. Thus, the U-phasefirst bus bar 71, the U-phase second bus bar 72, the V-phase first busbar 73, the V-phase second bus bar 74, the W-phase first bus bar 75, andthe W-phase second bus bar 76 having different shapes from each othermay be manufactured at low cost. As described above, by using the wire77 for the bus bar 70, it is easy to cope with a small quantity batchproduction. Further, a design change of the bus bar 70 may be easilycoped with. Further, by using the wire 77 for the bus bar 70, the numberof wires 77 which becomes unnecessary is reduced as compared with thepress processing, thereby improving the product yield of materials.

Further, each of the lead wire connection parts 71 a, 71 b, 72 a, 72 b,73 a, 73 b, 74 a, 74 b, 75 a, 75 b, 76 a, and 76 b has a U-shape thatopens in the radial direction. Thereby, it is not necessary to changethe posture of the welding jig 100 in the welding process. Accordingly,the manufacturing process may be simplified.

Further, by providing the first linear parts 71 s to 76 s, the dimensionof the bus bar 70 in the radial direction may be easily reduced ascompared with the case in which the bus bar 70 is curved withoutproviding the linear parts. Thus, the bus bar 70 and the bus bar unit 60including the same may be miniaturized. Further, by providing the firstlinear parts 71 s to 76 s, the first lead wire connection parts 71 a to76 a may be connected to the second lead wire connection parts 71 b to76 b at the shortest distance. Thereby, the use amount of the wire 77may be saved.

Accordingly, the bus bar 70 may be miniaturized, and the use amount ofthe wire 77 required to form the bus bar 70 may be saved.

According to the present example embodiment, the second ends 71 e to 76e are provided with the extending parts 71 f to 76 f extending in thedirection away from the openings 71 p to 76 p of the first lead wireconnection parts 71 a to 76 a. Thereby, the positional displacement ofthe welding jig 100 may be suppressed when welding the first lead wireconnection parts 71 a to 76 a and the second lead wires 45. Thus, thefirst lead wire connection parts 71 a to 76 a may be stably held, sothat the process of welding the first lead wire connection parts 71 a to76 a and the second lead wires 45 may be stably performed.

According to the present example embodiment, the second lead wireconnection parts 71 b to 76 b include the first linear parts 71 s to 76s and the second linear parts 71 t to 76 t at both ends thereof throughthe third ends 71 h to 76 h and the fourth ends 71 i to 76 i. Thereby,the positional displacement of the welding jig 100 may be suppressedwhen welding the second lead wire connection parts 71 b to 76 b and thesecond lead wires 45.

Further, the second linear parts 71 t to 76 t are parallel to the firstlinear parts 71 s to 76 s, and are arranged to be shifted from theimaginary lines L extending the first linear parts 71 s to 76 s. Thus,the plurality of bus bars 70 may be easily disposed while avoidinginterference therebetween.

According to the present example embodiment, the first lead wireconnection parts 71 a to 76 a and the second lead wire connection parts71 b to 76 b are arranged on concentric circles centered on the centralaxis J when viewed in the vertical direction. Thereby, when the bus barholder 61 is rotated about the central axis J when the first lead wireconnection parts 71 a to 76 a and the second lead wire connection parts71 b to 76 b are welded to the second lead wires 45, it is not necessaryto move the welding jig 100 and a laser welding nozzle in the radialdirection. Thus, the welding process may be performed efficiently.

According to the present example embodiment, each of the U-phase firstbus bar 71, the U-phase second bus bar 72, the V-phase first bus bar 73,the V-phase second bus bar 74, the W-phase first bus bar 75, and theW-phase second bus bar 76 is held by each clamping part 66 at each ofthe first linear parts 71 s to 76 s. Thereby, the positional accuracy ofthe first lead wire connection parts 71 a to 76 a and the second leadwire connection parts 71 b to 76 b, which are located on both sides ofthe first linear parts 71 s to 76 s, with respect to the second leadwires 45 may be improved. Further, when vibration is applied from theoutside, load applied to the first lead wire connection parts 71 a to 76a and the second lead wire connection parts 71 b to 76 b may besuppressed.

According to the present example embodiment, each of the bus bars 70 isheld by each of the clamping parts 66 between the first lead wireconnection parts 71 a to 76 a and the second lead wire connection parts71 b to 76 b. Thus, the positional accuracy of the first lead wireconnection parts 71 a to 76 a and the second lead wire connection parts71 b to 76 b may be improved. Further, when vibration is applied fromthe outside, load applied to the first lead wire connection parts 71 ato 76 a and the second lead wire connection parts 71 b to 76 b may besuppressed.

According to the present example embodiment, the plurality of bus bars70 include the cross parts J1 to J6 crossing each other when viewed inthe vertical direction, and one side of the pair of bus bars 70 crossingeach other includes the retracting part 93 passing above the other sideof the pair of bus bars 70 at the cross parts J1 to J6. Thereby, theU-phase first bus bar 71, the U-phase second bus bar 72, the V-phasefirst bus bar 73, the V-phase second bus bar 74, the W-phase first busbar 75, and the W-phase second bus bar 76 may be arranged whileminimizing the dimension in the vertical direction. Thus, the bus barunit 60 may be miniaturized.

Further, the U-phase first bus bar 71, the U-phase second bus bar 72,the V-phase first bus bar 73, the V-phase second bus bar 74, the W-phasefirst bus bar 75, and the W-phase second bus bar 76 may be held by theclamping parts 66. Thereby, it is possible to suppress the bus bars 70from coming into contact with each other at the cross parts J1 to J6even when vibration or the like is applied.

Further, in the U-phase first bus bar 71, the U-phase second bus bar 72,the V-phase first bus bar 73, the V-phase second bus bar 74, the W-phasefirst bus bar 75, and the W-phase second bus bar 76, the verticalpositions of at least the terminal connection parts 71 c to 76 c and thefirst lead wire connection parts 71 a to 76 a coincide with each other.As a result, it is not necessary to move the welding jig 100 and thelaser welding nozzle in the vertical direction. Thus, the weldingprocess may be performed efficiently.

According to the present example embodiment, in the U-phase first busbar 71, the U-phase second bus bar 72, the V-phase first bus bar 73, theV-phase second bus bar 74, the W-phase first bus bar 75, and the W-phasesecond bus bar 76, the vertical positions of the terminal connectionparts 71 c to 76 c and the first lead wire connection parts 71 a to 76 aare held by the clamping parts 66 at the same regions. Thereby, theU-phase first bus bar 71, the U-phase second bus bar 72, the V-phasefirst bus bar 73, the V-phase second bus bar 74, the W-phase first busbar 75, and the W-phase second bus bar 76 may be arranged whileminimizing the dimensions in the vertical direction. Thus, the bus barunit 60 may be miniaturized. Further, the vertical positions of theclamping parts 66 may be set at the same position.

Further, in the V-phase first bus bar 73, the V-phase second bus bar 74,the W-phase first bus bar 75, and the W-phase second bus bar 76, theclamping parts 66 hold the roots of the retracting parts 93, 94, 93A,93B, 94A, and 94B. Thereby, the positional accuracy of the terminalconnection parts 73 c to 76 c, the first lead wire connection parts 73 ato 76 a, and the second lead wire connection parts 73 b to 76 b may beimproved. Further, even when vibration or the like is applied, load maybe suppressed from being applied to the terminal connection parts 73 cto 76 c, the first lead wire connection parts 73 a to 76 a, and thesecond lead wire connection parts 73 b to 76 b.

According to the present example embodiment, the V-phase first bus bar73 and the V-phase second bus bar 74 include the retracting parts 93 and94 at portions crossing the U-phase first bus bar 71 and the U-phasesecond bus bar 72. The W-phase first bus bar 75 and the W-phase secondbus bar 76 include the retracting parts 93A, 93B, 94A, and 94B at eachportion crossing each of the U-phase first bus bar 71, the U-phasesecond bus bar 72, the V-phase first bus bar 73, and the V-phase secondbus bar 74. Thereby, the bus bars 70 may be assembled on the bus barholder 61 in the order of the U-phase first bus bar 71 and the U-phasesecond bus bar 72, the V-phase first bus bar 73 and the V-phase secondbus bar 74, the W-phase first bus bar 75 and the W-phase second bus bar76, so that the bus bar unit 60 may be assembled easily.

According to the present example embodiment, the motor 10 includes theabove-described bus bar unit 60. Thus, the bus bar 70 may beminiaturized, and the use amount of the wire 77 required to form the busbar 70 may be saved.

According to the present example embodiment, the motor 10 includes theabove-described bus bar unit 60. Thus, the first lead wire connectionparts 71 a to 76 a may be stably held, so that the process of weldingthe first lead wire connection parts 71 a to 76 a and the second leadwires 45 may be stably performed.

According to the present example embodiment, the motor includes theabove-described bus bar unit 60. Thus, it is possible to suppresssecurely the bus bars 70 from coming into contact with each other and toperform the welding process efficiently.

FIG. 9 is a view illustrating an apparatus to which the motor accordingto the example embodiment is mounted.

Next, an example embodiment of an apparatus to which the motor 10 of thepresent example embodiment is mounted will be described. In the presentexample embodiment, an example in which the motor 10 is mounted on anelectric power steering apparatus will be described. An electric powersteering apparatus 2 shown in FIG. 9 is mounted on a steering mechanismof a wheel of an automobile. The electric power steering apparatus 2 isan apparatus configured to reduce a steering force by hydraulicpressure. The electric power steering apparatus 2 includes the motor 10,a steering shaft 214, an oil pump 216, and a control valve 217.

The steering shaft 214 transmits an input from a steering 211 to an axle213 having wheels 212. The oil pump 216 generates hydraulic pressure ina power cylinder 215 that transmits a driving force by the hydraulicpressure to the axle 213. The control valve 217 controls oil of the oilpump 216. In the electric power steering apparatus 2, the motor 10 ismounted as a driving source of the oil pump 216.

The electric power steering apparatus 2 of the present exampleembodiment includes the motor 10 of the present example embodiment, andthus the bus bar unit 60 may be miniaturized, and the influence of amagnetic field on the outside may be suppressed.

Although the example embodiment of the present disclosure has beendescribed above, each configuration and combination thereof in theexample embodiment are an example, and addition, omission, replacement,and other modifications of the configuration are possible withoutdeparting from the spirit of the present disclosure. Further, thepresent disclosure is not limited by the example embodiment.

For example, the motor of the example embodiment described above is notlimited to being mounted on an electric power steering apparatus, andmay be mounted on any apparatus.

Further, in the above-described example embodiment, each of the bus bars70 has a configuration including each of the first lead wire connectionparts 71 a to 76 a and each of the second lead wire connection parts 71b to 76 b, but may have a configuration including three or more leadwire connection parts.

Features of the above-described preferred example embodiments and themodifications thereof may be combined appropriately as long as noconflict arises.

While example embodiments of the present disclosure have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present disclosure. The scope of the presentdisclosure, therefore, is to be determined solely by the followingclaims.

The invention claimed is:
 1. A bus bar unit that is provided in a motor,the bus bar unit comprising: a bus bar holder provided on one side in anaxial direction of a stator disposed in an annular shape around acentral axis extending in a vertical direction; a bus bar extendingalong a plane perpendicular to the axial direction and fixed to the busbar holder; and an external connection terminal connected to the bus barand extending upward from the bus bar; wherein the bus bar includes awire and a terminal connector located on one end thereof and connectedto the external connection terminal, a first lead wire connector locatedon the other end thereof and connected to a lead wire extending from thestator, a second lead wire connector located between the terminalconnector and the first lead wire connector, and a first linear portionto connect the first lead wire connector to the second lead wireconnector and having a linear shape when viewed in the axial direction;and each of the first lead wire connector and the second lead wireconnector have a U-shape that opens in a radial direction.
 2. The busbar unit of claim 1, wherein the first lead wire connector includes afirst end connected to the first linear portion and a second end locatedon the opposite side of the first end; and the second end is providedwith an extension that extends in a direction away from an opening ofthe first lead wire connector.
 3. The bus bar unit of claim 1, whereinthe second lead wire connector includes a third end connected to thefirst linear portion and a fourth end located on the opposite side ofthe third end; the bus bar includes a second linear portion extendingfrom the fourth end and having a linear shape when viewed in the axialdirection; and the second linear portion is shifted from an imaginaryline extending the first linear portion.
 4. The bus bar unit of claim 3,wherein the second linear portion is parallel or substantially parallelto the first linear portion.
 5. The bus bar unit of claim 1, wherein thefirst lead wire connector and the second lead wire connector arearranged on a concentric circle having the central axis as a center whenviewed in the axial direction.
 6. The bus bar unit of claim 5, wherein aplurality of bus bars are included; and the first lead wire connectorand the second lead wire connector of each of the bus bars are arrangedon a concentric circle having the central axis as a center when viewedin the axial direction.
 7. The bus bar unit of claim 1, wherein the busbar holder includes a clamp to hold the bus bar by fitting the bus barthereinto; and the bus bar is held in the clamp at the first linearportion.
 8. A motor comprising: the bus bar unit of claim 1; the statoraround which a coil wire is wound; and a rotor facing the stator in theradial direction through a gap.